Extremely patchy artist can ultimately paint such a shrub (10)

I believe the answer is:

pyracantha

I'm a little stuck... Click here to teach me more about this clue!

'shrub' is the definition.
Both the definition and answer are singular nouns.
Maybe there's a link between them I don't understand?

'extremely patchy artist can ultimately paint such a' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'ultimately' says to take the final letters.
'patchy' with its centre removed is 'py'.
The last letters of 'paint such' are 'th'.
'py'+'ra'+'can'+'th'+'a'='PYRACANTHA'

Can you help me to learn more?

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.